Production of cement and the like



O DORMANN PRODUCTION oF CEMENT AND THE LIKE Feb. 19 ,.1924

Patented Feb, 19, 1924. Y v

OTTO DORMANN, OF STETTIN, GERMANY.

PRODUCTION F CEMENT AND THE LIKE.

Application filed May 25, 1922. Serial No. 563,503.

To all whom it may concern.' i the gases and ultimately lead to high losses 55 Be it lmown that I, Oi'io DORirANN, a of heat in the waste gases. citizen of Germany, residing at Stettin, Gier It is therefore necessary to provide a many, have invented certain new and useful means for carr ing through a thorough Improvements in the Production of .Cement combustion of tlile fuel immediately before and the like (for which I have iled an apthe sintering zone, that is in the so-called 60 lication in Germany, July 2, 1920, and zone `of calcination of the revolving .fur-Y ermany, March 30, 1921), *of which the nace. t To eect this in the sinteriug zone following is a specification. itself appears to be useless and in view of My invention relates to the production of the singular behaviour of Portland cement cement and the like, more particularly Portin the sintering zone itself does not even e5 land cement. It is one of the main objects seem practicable.

' of the presentinvention to render manufac- It, has therefore been proposed to dam-up ture of cement more efficient and more the burning gases by introducing steam jets. economical. Obviously this mode of proceeding had n0 More recent investigations have estabichance of a success, considering the fact lished the fact that-,the sintering reaction that the steam would sooner act towards occurring in the production of Portland celowering, than towards increasing the vement is an exothermic reaction, accompanied ,locity of combustion. Moreover the quantity 20 by an evolution of heat. In consequence of the burning gas would be increased in a thereof no supply of heat from outside is highly uneconomical manner by the steam required in the sinteiing zone of the recharged with high specific heat and the vevolving furnace, it being merely necessary locity of the gases further increased whereto cover the losses occasioned by heat conby the advantages resulting from such darn- 26 vection and radiation/and, if necessary, to ming--up'are fully balanced,

heat the material to the temperature re- In reality the highest velocity of combusquired for starting the reaction and to keep tion is obtained solely by the perfect mix# it on this temperature. The real demand ture of fuel and nir before and during comfOr a Supply 0f heat in the revolving furbustion. In the revolving furnace for the 3o nace begins in a zone which lies in the diproduction of Portland cement the point rectioii of travelling of the material above where the highest velocity of combustion l 01 behind the ZOIle 0f Sillelng et e Peint must be obtained, lies before the sintering where the endothermic or heat consuming" zone, that is, in the zone of calcination. reaction forexpelling the carbonio acid and It, has been tried to improve combustion 35 the hydrate Wetertekee PleCe- In and beby introducing further air through the'fur- OIG this ZOIie, that iS directly abOVG the nace Wall by Way 0f e, number of 0pen1ng5 90 sintering zone the highest temperature must` However, Such introduction of air does not be obtained; for the. higher the difference Sufce as Such for raising the velocity of of temperature between the re gases and combustion so high that instead of the long 40 the material to be calcined, the higher the ame hitherto produced in the revolving degree 0f eeelleyfurnace a short hot flame would be obtained, 95

In the usual type of revolving furnace inasmuch as the freshly introduced air travthe ame of coal-dust, gas or the like proelling in the direction of the fuel. gases canduced under pressure is taken up by the not act towards effecting an intimate mix- 45 draft of the furnace and with the high ture of fuel and air. t

velocity of the gases only a comparatively This c an only be effected according to the y slow combustion is obtained, a long flame present invention by forcing this secondary being formed. In this case the difference air into the furnace under highpressiirean between the temperatures of the iiie gases more or'less at an acute angle in a direction '50 and the material, and in consequence the-reopposed to that of the gases. Only by proof the efficiency are onl low. In order, cecding in. this manner the formation of I therefore, to attain a resu t, large quantities strong. eddies will be obtained which secure of fuel must be used, which naturally act an intimate mixture of fuel and air and the towards a. further increase of velocity of highest combustion velocity obtainable. At

the same time the gases. are dammed-up in such way that they will not pass across the material at a higher speed than is consistent with. the transmission of heat onto thel material.

is a particular object of the present `inl vention to attainthis result in the most perfect manner. 'Io this end I' cause a current y of air to be forced before the sintering zone,

Q heat ofthe gases of combustion whereby the obtention of the desired high temperature at jthe required place is facilitated. This method can be further improved by admixing to the material to be calcined a certain quantity of fuel such as small coke or the like. In the places where this mixture covers the air nozzles through which the secondary air enters .the furnace, the air is forced through it and causes a combustion of the fuel with .particularly high eliciency.

tersthe' furnace through apertures o, its directlon of flow being opposed to that of the furnace adapted for use 35 In .the drawings affixed to this specificamenate v fuel current. rIhe secondary air of combus special means disclosed in the'specification l ^and in the drawings appertaining thereto, for obvious modifications will occur to a person skilled in the art.

I claim: v ff 1. The method of producing cement, and more particularly Portland cement, consisting in heating the raw material in a revolv- 1ng furnace and damming-up Aor choking the vheating gas current in the zone of calcination by a veil yof air substantially extending transversely across the furnace.

2. 'Ihe method of.producingv cement, and more particularly Portland cement, consisting in heating the raw material in a revolving furnace and forcing partof the air re- Iqulred. for combustion into the calcinating zone ofthe furnace in such manner as to -damu or chokethev heating gas current.

3. Tile method of producing cement, and more particularly Portland cement, consisting in vheating theraw material in a revolv-` ing furnace and forcing part of the air re'- qulred for combustion into the calcinating tion andv forming` part thereof a revolving/zonevof the furnace in suchmanner as to l inl carrying out my A.invention is illustrated by .way of example in diagrammatic section.

In the drawing a is the furnace and b is the current of air serving in a'well known `manner to lintroduce the fuel into thel furnace. Ihe secondary air of combustion encurrent b, whereby a veil is formedwhich fills the entire section of the furnace andv acts as above described. In the example illustrated the material to be converted into cement is introduced into the` furnace through the tube d and travels throughthe furnace in a directibn counter to that ofthe form a veil of air substantially extending transversely across the furnace.

4. The method of producing cement, and

more particularly Portland lcement, consistof the burning gases.

In testimony whereof I aflix my signature.

. y OTTO DURMANN. i Witnesses: i E. I-IoLTzERMAN,

' R. T. ALLTPAGE.

jets travelling in a direction counter to` that K 

